U.S. patent number 4,209,898 [Application Number 05/940,353] was granted by the patent office on 1980-07-01 for assembly line for parts of electronic and other equipments.
This patent grant is currently assigned to Hitachi, Ltd.. Invention is credited to Jun Aoki, Takashi Hayashida, Shigesabroh Komatu, Seii Miyakawa, Naoki Takahasi.
United States Patent |
4,209,898 |
Aoki , et al. |
July 1, 1980 |
Assembly line for parts of electronic and other equipments
Abstract
An assembly line for parts of electronic and other equipment
having a plurality of assembling stations, each station including a
conveyor belt for successively conveying articles from the adjacent
station, a drive source for the conveyor belt, means for stopping
each of the articles including a stop lever for engaging a boss
attached to each article for stopping each article in an operating
position, means for positioning each article including a
positioning pin for insertion in a hole formed in each article for
positioning the article stopped in the operating position, a
picking and placing unit for assembling each part with one of the
articles after parts are successively fed by a supplying device,
and an assembly line base machine provided with an operating panel
for operating the drive source, article stopping means, article
positioning means and picking and placing unit. Shifting of the
stations and reorganization of the assembly line itself can be
readily carried out.
Inventors: |
Aoki; Jun (Katsuta,
JP), Hayashida; Takashi (Mito, JP), Komatu;
Shigesabroh (Katsuta, JP), Miyakawa; Seii
(Yokohama, JP), Takahasi; Naoki (Yokohama,
JP) |
Assignee: |
Hitachi, Ltd.
(JP)
|
Family
ID: |
14494897 |
Appl.
No.: |
05/940,353 |
Filed: |
September 7, 1978 |
Foreign Application Priority Data
|
|
|
|
|
Sep 12, 1977 [JP] |
|
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52-108840 |
|
Current U.S.
Class: |
29/783; 29/701;
29/784; 198/345.3; 29/742; 29/794 |
Current CPC
Class: |
G05B
19/41815 (20130101); H05K 13/028 (20130101); H05K
13/0495 (20130101); H05K 13/0053 (20130101); B23P
21/004 (20130101); Y10T 29/53365 (20150115); Y10T
29/53413 (20150115); Y02P 90/02 (20151101); Y10T
29/53004 (20150115); Y10T 29/5337 (20150115); Y02P
90/08 (20151101); G05B 2219/45029 (20130101); G05B
2219/31019 (20130101); Y02P 90/04 (20151101); Y10T
29/53187 (20150115) |
Current International
Class: |
B23P
21/00 (20060101); G05B 19/418 (20060101); H05K
13/00 (20060101); H05K 13/04 (20060101); H05K
13/02 (20060101); B23P 021/00 () |
Field of
Search: |
;29/701-704,783,784,787,791,794-797,742,759 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Hall; Carl E.
Attorney, Agent or Firm: Craig and Antonelli
Claims
We claim:
1. An assembly line for parts of electronic and other equipment
having a plurality of assembling stations for carrying out a
plurality of production steps, said assembly line comprising:
a table assigned to each one of said plurality of assembling
stations and each table having mounted thereon:
(a) endless conveyor means mounted on an upper surface of the table
across thereof and movable from one end to the other end of the
table;
(b) a drive source for driving said endless conveyor means;
(c) stopping means comprising a stop lever for engaging an article
conveyed by said endless conveyor means to stop the article in an
operating position;
(d) positioning means comprising a positioning pin for insertion in
a hole formed in said article stopped by said stopping means in the
operating station so as to thereby engage the article and correctly
position the same in the operating position; and
(e) operating means for performing an operation with the article
positioned in the operating position in accordance with a
predetermined schedule; and
a sequence controller provided for each of said assembling stations
for effecting sequence control of a series of operations performed
by various elements in each station including actuating said
stopping means and said positioning means to stop and position in
said operating position an article supplied by said endless
conveyor means across said table, actuating said operating means to
perform a predetermined operation with said article, and releasing
said positioning means to convey the article again by said endless
conveyor means upon completion of the performance of the
operation;
said tables and said sequence controllers in said plurality of
assembling stations capable of being arranged in any combination as
desired to provide an assembly line suitable for performing a
plurality of different assembling operations.
2. An assembly line as claimed in claim 1, further comprising
switches mounted at each table for producing signals for rendering
said sequence controller operative and inoperative.
3. An assembly line as claimed in claim 1, further comprising a
plurality of lamps mounted at each table for indicating the
misoperation of said operating means, said stopping means and said
positioning means.
4. An assembly line as claimed in any one of claims 1, 2 and 3,
wherein said endless conveyor means comprises at least two endless
conveyor belts arranged parallel to each other, said endless
conveyor belts being brought into frictional engagement with ribs
formed on the underside of each article for conveying the article
as the belts move.
5. An assembly line as claimed in claim 4, further comprising guide
rail means arranged to cross the table from one end thereof to the
other end thereof and interposed between said two endless belts of
said endless conveyor means in parallel therewith, said guide rail
means being brought into engagement with one of a boss and a groove
formed on the underside of each article whereby said guide rail
means can guide the article as the latter is conveyed by the
endless conveyor means from one end of the table to the other end
thereof.
6. An assembly line as claimed in any one of claims 1 to 3, wherein
said operating means comprises a supplying machine for successively
aligning and feeding a number of parts to cause each part to be
positioned in a predetermined position, and a picking and placing
unit for holding the part positioned in said predetermined position
in the supplying machine and assembling the part with the article
stopped and positioned in the operating position, said supplying
machine and said picking and placing unit being adapted to be
rendered operative by instructions from said sequence
controller.
7. An assembly line as claimed in claim 4, wherein said operating
means comprises a supplying machine for successively aligning and
feeding a number of parts to cause each part to be positioned in a
predetermined position, and a picking and placing unit for holding
the part positioned in said predetermined position in the supplying
machine and assembling the part with the article stopped and
positioned in the operating position, said supplying machine and
said picking and placing unit being adapted to be rendered
operative by instructions from said sequence controller.
8. An assembly line as claimed in claim 5, wherein said operating
means comprises a supplying machine for successively aligning and
feeding a number of parts to cause each part to be positioned in a
predetermined position, and a picking and placing unit for holding
the part positioned in said predetermined position in the supplying
machine and assembling the part with the article stopped and
positioned in the operating position, said supplying machine and
said picking and placing unit being adapted to be rendered
operative by instructions from said sequence controller.
Description
BACKGROUND OF THE INVENTION
This invention relates to an assembly line for parts of tape
recorders, radios, etc., which are electronic or other equipment,
wherein a multiplicity of parts are assembled into finished
products.
Heretofore, a free cycle working line has been known which, as
disclosed in U.S. Pat. No. Re 25,886, includes a chain conveyor for
conveying parts and a drive source for the chain conveyor which are
for all the working or assembling stations. Pallets which support
workpieces thereon and conveyed by the chain conveyor are each
stopped and positioned in each station, and each of the workpieces
is worked by a working machine in each station. The free cycle
working line of the prior art has a disadvantage in that, when
trouble occurs in any of the working machines mounted in the
stations or the chain conveyor or the drive source fails, operation
must be suspended in the entire working line, thereby causing a
great reduction in the rate of operation. Particularly, when a
single free cycle working line has several scores of stations, the
chain conveyor must be stopped often and the operation must be
suspended in the entire working line, if a failure occurs in the
connection between the chain conveyor and the working machine in
any of the stations. Thus, this type of working line has been very
low in the rate of operation.
SUMMARY OF THE INVENTION
This invention has as its object the provision of an assembly line
for parts of electronic and other equipment wherein operation can
be continued without interruption in the entire working line, even
if trouble occurs in any one of the stations.
The characterizing features of this invention are that the assembly
line includes a plurality of tables, one for each station, and each
table has mounted thereon a guide rail extending across the surface
of the table, an endless conveyor mounted along the guide rail for
successively conveying articles by frictional engagement of the
articles with the conveyor by the weight of the articles while a
boss or a groove formed in a lower end of each article is fitted in
a guide rail to be guided thereby a drive source for driving the
endless conveyor, article stopping means including a stop lever
located in an operating position in each station for engaging a
member projecting from each article to stop each article in the
operating position, article positioning means including a
positioning pin located in the operating position for insertion
into a hole formed in each article to correctly position each
article in the operating position, and an operating unit for
executing a predetermined operation with each article stopped and
positioned in the operating position by the article stopping means
and the article positioning means respectively. A sequence
controller for effecting control of a series of operations
performed by various means and operating unit is provided for each
station, whereby operation can be performed independently in each
station in the assembly line and shifting of the stations and
reorganization of the assembly line itself can be carried out
readily.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary perspective view of the assembly line for
parts of electronic and other equipments according to this
invention;
FIG. 2a is a perspective view, on an enlarged scale, of one of the
assembling stations shown in FIG. 1;
FIG. 2b is an explanatory view showing the path of movement of a
chuck holding the parts which is provided in a picking and placing
unit;
FIG. 3 is a front view, partly shown in section, of the article
stopping means and the article positioning means of the assembly
line shown in FIG. 1;
FIG. 4 is a sectional view taken along the line IV--IV in FIG. 3;
showing the relation between a portion of an article and the guide
rail;
FIG. 5 is a view, partly shown in section, showing the manner in
which an article is positioned by inserting the positioning pin in
a hole formed in the article;
FIG. 6 is a flow chart for assembling parts with an article;
FIG. 7 is a flow chart showing operations performed by actuating
switches mounted on the operating panel shown in FIGS. 1 and 2;
and
FIG. 8 shows the outline of operation of a unit for controlling the
assembling machine, supplying machine and base machine of each
assembling station.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a perspective view partly showing the assembly line for
parts of electronic and other equipments according to this
invention. An article 6 may be, for example, an electronic
equipment, such as a tape recorder, and the parts assembled
comprise various types of operating parts, various types of links,
various types of pivotal arms, various types of rotating members,
various types of springs, various types of belts, a head assembly,
switching mechanisms and balls. The assembly line for assembling
the article 6 has 30-60 assembling stations arranged, for example,
in the form of a letter U and including a station in which a
chassis is placed on a conveyor, a station in which each of the
aforesaid various parts is assembled with the chassis, a station in
which a screw tightening operation is performed and other stations
for performing various different operations.
Each station of the assembly line includes a base machine 1 having
the function of conveying, stopping and positioning the article 6
and capable of being used in any of all the stations, a part
supplying and assembling section 5 corresponding to the base
machine 1 for effecting aligning, feeding, separation and
assembling of parts, and an operating panel 30 for controlling
these operations and giving indications. One sequence control
device 45 is provided for several stations. In the sequence control
device 45, there are provided several sequence controllers 27 which
are associated with one for each station for effecting sequence
control of a series of operations performed in said each station.
The base machines 1 of these independent stations are successively
connected one to another simply by means of two bolts 29 shown in
FIG. 2a. The base machine 1 constituting each assembling station
includes a rectangular table 2. 3 designates a conveyor belt for
conveying the article 6 by being maintained, by the weight of the
article 6, in engagement with four ribs 6a projecting from the
underside of the article 6. The conveyor belt 3 consists of two
belt members located parallel to each other and trained over
pulleys 3a rotatably mounted in cutouts 2a formed at opposite ends
of the table 2. 4 designates a motor mounted on the lower left side
of the table 2 for driving the pulleys 3a.
7 designates a guide rail in the form of a groove of the U-shape in
cross section for guiding bosses 11 and 12 attached to the article
6. The guide rail 7 extends from the left end to the right end of
the surface of the table 2 and is interposed between the belt
members of the conveyor belt 3.
Referring to FIG. 3, 8 designates a stop lever adapted to come into
engagement with the front of the boss 12 of the greater length
attached to a leading end portion of the article 6. The stop lever
8 is pivotally supported at 8a for movement in an opening 7a formed
in a predetermined position in the guide rail 7 and normally urged
to move clockwise by the biasing force of a spring 9. 13 designates
a first switch mounted on the underside of the guide rail 7 for
detecting the contact of the stop lever 8 with a stopper surface 10
of the opening 7a and the stopping of the article 6 in an
assembling position (operating position) of each assembling
station. 14 designates a stopper cylinder mounted on the underside
of the table 2 for vertically moving in reciprocatory movement a
plate for supporting the pivot 8a of the stop lever 8. 15 is a
positioning cylinder mounted on the underside of the table 2 and
having an output shaft located vertically and connected to a
positioning pin 16 having a pointed forward end for projection
through an opening formed in a guide bush 7b attached to a
predetermined position in the guide rail 7 to be inserted in a hole
11a formed in the boss 11 of the article 6, so as to position the
article 6 in the assembling position (operating position) by using
the guide bush 7b as a reference. 17 is a second switch mounted on
the underside of the table 2 for detecting that the positioning pin
16 has moved upwardly to correctly position the article 6, the
second switch 17 having an actuating arm adapted to come into
engagement with a projection formed in the positioning pin 16.
Referring to FIG. 2, 19 designates a parts feeder storing therein a
large number of parts 22 to be assembled with the article 6, the
parts feeder 19 successively aligning the parts 22 serially and
feeding them by vibration to a straight line feeder or a gravity
chute 20. 21 designates a separating section in which the parts 22
are successively separated from one another, after they are moved
straight forwardly by vibration through the straight line feeder or
fed by gravity while remaining in an inclined position. In the
separating section 21, a pawl which has engaged and restrained the
foremost part 22 of the group of parts 22 is disengaged to release
the first part 22, and the next following part 22 is held in
position as by the pressure of a spring, so that the parts 22 will
be successively separated from one another and the separated part
22 will be positioned, by being forced by a cylinder 21a, against a
reference wall (reference position) in a portion which is in the
form of a groove. 23 is a third switch for detecting that the part
22 is positioned in the reference position.
18 designates a picking and placing unit, serving as an assembling
machine, which is mounted on the table 2 and which has attached to
its forward end a chuck 32 having a pin inserted in a reference
hole (not shown) formed in the part 22 positioned in the separating
section 21. The chuck 32 grips the part 22 by electromagnetic or
vacuum adhesion to move it from the reference position in the
separating section 21 to an assembling position in the article 6.
The chuck 32 is moved up and down in a predetermined amount by
means of a cylinder 24a, and is moved back and forth a
predetermined amount by means of a cylinder 24b, so that the part
22 will be conveyed through a path in the form of a portal. 25a is
a switch for detecting the upper limit of the chuck 32, while 25b
is a switch for detecting the lower limit of the chuck 32. 26 is a
switch for detecting that the chuck 32 has held the part 22 and is
positioned in a front end of the assembling position.
30 designates an operating panel for effecting control of operation
of the base machine 1 for each assembling station. The control
panel 30 has mounted thereon a centralized/individual change-over
switch 30a for switching between a centralized automatic operation
of all the base machines 1 of the number of assembling stations and
an individual operation of the single base machine 1 of one
assembling station, an automatic/manual change-over switch 30b for
switching between an automatic operation and a manual operation, an
automatic starting switch 30c which is actuated when it is desired
to perform an individual automatic operation, a base machine switch
30d which is actuated when it is desired to perform an individual
operation to allow only the motor 4 to be driven so as to
continuously convey the articles 6 from the right end to the left
end, without operating the parts feeder 19, a supplying machine 44
including the straight line feeder or the chute 20, the assembling
machine 18, the positioning cylinder 15, and the stopper cylinder
14, a one cycle switch 30e which enables the supplying machine 44,
the assembling machine 18, and the article conveying and
positioning means (the motor 4, positioning cylinder 15, and
stopper cylinder 14) through one cycle only, an emergency stop
switch 30l which renders all the mechanisms inoperative in case of
emergency, an emergency suspension indication lamp 30f for
indicating that all the operations are suspended in case of
emergency, an abnormal assembling indication lamp 30g for
indicating that the assembling machine 18 is in trouble, an
abnormal supply indication lamp 30h for indicating that the parts
feeder 19 and the supplying machine 44 including the straight line
feeder or gravity chute 20 are in trouble, a button 30j for
checking the lamps, and a reset button 30k for putting out the
aforesaid lamps. 31a is a switch for driving the motor 4 only. 31b
is a switch for driving the stopper cylinder 14 only. 31c is a
switch for driving the positioning cylinder 15. 31d is a switch for
driving the cylinder 24b for moving the chuck 32 of the picking and
placing unit 18 back and forth. 31e is a switch for driving the
cylinder 24a for moving the chuck 32 of the picking and placing
unit 18 up and down. Besides, there are provided a switch for
driving the parts feeder 19, and a switch 31f for driving the
cylinder for positioning the part 22 in the reference position.
These switches are designed to actuate, individually and manually,
the drive for each of the supplying machine 44, the assembling
machine 18 and the article conveying and positioning means.
However, when all the stations are operating normally, no abnormal
signal 34 is produced by the sequence controller 27 of each
station, so that the assembly line is ready for centralized
operation. Thus, by setting the centralized/individual change-over
switch 30a at the centralized operation, a control unit 30m mounted
in the operating unit 30 produces a centralized automatic operation
signal 33 which is supplied, through an interface circuit 36.sub.1,
to a central processing unit (CPU) 37. The central processing unit
37 in turn supplies a sequence start signal 35 to the sequence
controllers 27 of all the assembling stations. Thus, the parts
supplying machine 44 is actuated to start operation and the motor 4
of the base machine 1 is actuated too, so that the supplying
machine, the assembling machine and the all the cylinders of the
base machine are operated in sequence in all the assembling
stations. In this way, operations are executed in many assembling
stations while the operations are centrally controlled by means of
a computer.
The operation of the assembling stations will now be described. The
motor 4 is actuated to drive the conveyor belt 3 and the article 6
which is supported on the conveyor belt with its ribs 6s being in
engagement with the conveyor belt 3. The article 6 moves in the
direction of an arrow shown in FIG. 1 while being guided by the
guide rail 7 which has inserted in its groove the bosses 11 and 12
of the article 6. As shown in FIG. 3, the bosses 11 and 12 have
their lengths set beforehand in such a manner that the boss 11 does
not impinge on the stop lever 8 and the boss 12 impinges on the
stop lever 8. When the article 6 conveyed from the previous station
reaches the illustrated assembling position, the boss 12 attached
to the article 6 causes the stop lever 8 disposed in a position A
to move to a position B, against the biasing force of the spring 9,
in which the stop lever 8 abuts against the stopper surface 10 and
becomes stationary. And, as shown in FIG. 6, the arrival of the
article 6 at the predetermined position is detected by the first
switch 13 which produces a limit switch signal 39 and supplies the
same to the sequence controller 27, which in turn produces and
supplies a drive signal 41 to the positioning cylinder 15 to
actuate the latter. Thus, the positioning pin 16 is moved upwardly
as shown in FIG. 5. The article 6 can be correctly positioned as
the positioning pin 16 of the positioning cylinder 15 is fitted in
the hole in the boss 11 of the article 6. Upon the article 6 being
thus positioned, the second switch 17 detects this positioning, and
a drive signal 41 from the sequence controller 27 actuates the
stopper cylinder 14 to move the stop lever 5 downwardly. Upon the
stop lever 8 being released from engagement with the boss 12
attached to the article 6, the stop lever 8 is restored to its
original broken line position by the biasing force of the spring 9
while remaining in its lower position. Meanwhile the second switch
17 produces and applies a limit switch signal 39 to the sequence
controller 27 to actuate the same, with the result that the
sequence controller 27 is actuated to give the drive instructions
41 to the assembling machine 18. Thus the picking and placing unit
18 begins to assemble the part 22 with the article 6.
The flow of the parts 22 to be assembled with the articles 6 will
be described. The parts stored in the parts feeder 19 are aligned
in a predetermined direction. The aligned parts are transferred to
the chute 20 where they remain stationary. One part which is
necessary is separated from the parts in the separating section 21
which is located posterior to the chute 20. The separated part 22
is moved by the picking and placing unit 18 to the assembling
position where it is assembled with the article 6. The movement of
the chuck 32 provided in the picking and placing unit 18 completes
one cycle when it has moved through a-b-a-c-d-c-a points shown in
FIG. 2b. Point a is the starting point. The third switch 23 for
separation detects that the part 22 is located in the reference
position in the separating section 21 and causes the chuck 32 of
the picking and placing unit 18 to move from starting point a to
point b, so that the reference pin extending from the chuck 32 will
be inserted in the reference hole formed in the part 22 to enable
the chuck 32 to hold the part 22 by electromagnetic or vacuum
adhesion. Then, the chuck 32 is moved upwardly by the cylinder 24a
for moving the chuck 32 up and down and moved forwardly by the
cylinder 24b for moving the chuck 32 back and forth, so that the
chuck 32 of the picking and placing unit 18 holding the part 22
waits, at point c, for the article 6 to be conveyed to the
assembling position. When the switch 25 detects that the chuck 32
holding the part 22 is located in the forward position and the
second switch 17 detects that the article 6 is positioned in the
assembling position, the cylinder 24a for moving the chuck 32 up
and down is actuated, so that the chuck 32 will continue its
movement from point c to point d and the motor 4 will be rendered
inoperative. As the chuck 32 releases the part 22 at point d, the
part 22 is assembled with the article 6. At this time, the part 22
to be assembled moves downwardly while being guided by the
reference pin of the chuck 32 when the part 22 is placed on the
article 6. If the part 22 is assembled in a correct position, this
is detected by a photoelectric detecting means mounted at the
forward end of the chuck 32 and consisting of a light source and a
light receiving element or by an electrically conducted detecting
means including a brush-like member mounted in a predetermined
position for electrically conducting the assembled part 22, thereby
completing assembling.
The motor 4 may be driven by a signal from a switch for detecting
the completion of assembling or the switch 25b for detecting the
lower limit of the picking and placing unit 18. The chuck 32 of the
picking and placing unit 18 then moves through points d, c and a to
wait at point a for the next part 22 to be supplied to the
separating section 21. When the switch for detecting the completion
of assembling of the part 22 with the article 6 by means of the
picking and placing unit 18 produces a signal, the signal is
supplied to the positioning cylinder 15 to move the positioning pin
downwardly to its original position. Downward movement of the
positioning pin 16 actuates the stopper switch 17 and the stopper
cylinder 14. At the same time, the stop lever 8 is completely
restored to its original broken line position. The motor 4 also
drives the conveyor belt 3 to convey the article 6 to the next
following station. The aforementioned cycle of operations is
repeatedly performed to assemble the part 22 with each article 6.
The sequence controller 27 is used for controlling the aforesaid
series of operations. The operating panel 30 for controlling these
operations is arranged in each station. According to one embodiment
of the operating panel 30, the base machine switch 30d is intended
only for moving the conveyor belt 3 and is actuated when the
picking and placing unit 18 is in trouble or under repair, and
assembling of the parts 22 with the articles 6 is carried out
manually, so that the articles 6 will be conveyed to the next
following station independently of the picking and placing unit 18.
As shown in FIG. 1, a manual operation space 28 is provided in each
station to accommodate the legs of the operator and to enable the
operator to perform operations with ease while sitting or squatting
on the floor. A space is formed on the table 2 for placing
magazines for storing a large number of parts therein. Thus, even
if the parts supplying machine 44 or picking and placing unit 18
fails, the belt 3 can be only driven and assembling of the parts 22
with the articles 6 can be executed manually by setting the
centralized/individual changeover switch 30a at an individual
operation, by setting the automatic/manual change-over switch 30b
at an automatic operation and by actuating the base machine switch
30d to only move the belt 3.
As aforesaid, the adjacent two assembling stations are
interconnected by the two bolts 29. Thus, by releasing the two
bolts 29, it is possible to rearrange the stations. Also, if the
base machine 1 operates normally as shown in FIG. 7, the limit
switch signal 39 of the picking and placing unit 18, the supplying
machine 44 and the base machine 1 of each station operates
normally. Supply of the part, holding of the part by the chuck, and
assembling of the part with the article are detected as by a
photoelectric detecting means and a signal 40 is produced when
there is no abnormality. No abnormal signals 43a, 43b and 43c (FIG.
8) are not supplied to the interface circuit 36.sub.1. At this
time, if the centralized/individual change-over switch 30a is set
at a centralized operation, all the sequence controllers 27 are
actuated by instructions from the central processing unit 37 and
the conditions of all the stations are indicated on an indication
panel of the central processing unit 37, so that the operation can
be performed by centralized control.
When it is impossible to place all the assembling stations under
centralized control, the centralized/individual change-over switch
30a is set at an individual operation and, if the station of
interest is normal, the automatic/manual change-over switch 30b is
set at an automatic operation and the automatic start switch 30c is
turned on, so as to supply an operating signal 42 (See FIG. 8) from
the control unit 30m to the sequence controller 27. Thus, the
operations can be performed individually and automatically in this
station and automatic assembling of the part with the article can
be performed. Also, when jamming of the parts, misoperation of the
chuck in gripping the part or other trouble occurs in a certain
station, it is possible to operate the drive source (load) of the
portion, which has failed, by means of any one of the signals 31a
to 30f to effect repair immediately and restore normalcy, by
setting the automatic/manual change-over switch 30a at a manual
operation. When normalcy is restored, the automatic/manual
change-over switch 30a is set at an automatic operation. When the
station is thus switched from a manual operation to an automatic
operation, it is possible to ascertain whether the station operates
normally, by turning on the one cycle assemble switch 30e so as to
automatically carry out assembling of the part through one cycle.
The control unit 30m comprises a circuit for shaping the signals
from the switches 30a to 30e, 30l, 30k and 31a to 31f for
introduction into the sequence controller 27.
In the embodiment shown and described hereinabove, the article 6 is
guided by the guide rail 7 by means of the bosses 11 and 12
attached to the underside of the article 6 and fitted in the groove
in the guide rail 7. It is to be understood that the invention is
not limited to this arrangement, and that the article 6 can be
guided by the guide rail which is in the form of an elongated bar
and received in a groove formed on the underside of the article
6.
From the foregoing description, it will be appreciated that the
invention makes it possible to alternately perform an automatic
assembling operation by using a picking and placing unit and a
manual assembling operation in each assembling station of an
assembly line. By this feature, the invention enables the operating
rate of the assembly line to be greatly increased, because the
operation can be switched instantanously from automatic to manual
in a certain station in which the source of trouble in the
supplying machine and picking and placing unit can be readily
removed or the supplying machine and picking and placing unit are
not fit for use because of an alteration made in the parts handled,
without suspending operation not only in the adjacent two
assembling stations but also in all the stations in the line.
According to the invention, the base machine of each station can be
readily replaced by another base machine which has been placed in
reserve, in case trouble occurs in the base machine or the
supplying machine and the picking and placing unit, which require
adjustments of their positions in the station relative to the base
machine, cannot readily be repaired on the spot. Thus, little
influence is exerted on the assembling stations adjacent the
station in which trouble has occurred in the base machine, thereby
enabling to minimize a reduction in the rate of operation.
According to the invention, it is possible to let each station
operate independently of other stations. By virtue of this feature,
if the operator is assigned to a station in trouble, assembling of
parts with the articles and repair and adjustments of the
mechanisms can be carried out simultaneously, thereby minimizing
influences which would be exerted on the adjacent stations or the
assembly line in general.
According to the invention, the stations of the assembly line are
independent of one another and the base machine has versatility.
This feature enables reorganization of the assembly line to be
effected readily without forming a new line when there is a change
in the model of the products to be handled. Thus, a new assembly
line suitable for products of a new model can be readily organized
with low cost, so that the assembly line according to the invention
has very great economical effects.
The table of the stations of the assembly line according to the
invention can be freely connected or disconnected. When the tables
are connected, the guide rails of the tables can be brought into
alignment with one another. This is also the case with the conveyor
belts, so that articles can be conveyed on the conveyor belts from
one station to another without let or hindrance.
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